This invention relates generally to imaging systems and more particularly, to pole pieces used with magnetic resonance imaging (MRI) systems.
At least some known MRI systems include pole pieces and magnets which are used to generate magnetic fields that are applied via the pole pieces to an imaging volume, such as a patient. However, problems may arise when a rapidly time-changing magnetic field is applied to the pole pieces. More specifically, because the pole pieces are fabricated from electrically conducting materials during operation of the MRI system, eddy currents may be created, which may generate magnetic fields that oppose the magnetic field being applied.
More specifically, applying a rapidly time-changing magnetic field may also cause a residual or secondary magnetic field to be induced in the pole pieces, which may remain after the applied magnetic field is removed. The eddy currents and the residual magnetization may both distort the applied magnetic field causing the image created from the applied magnetic field to also be distorted.
Accordingly, to facilitate improved operation of the MRI system, at least some known MRI systems include pole pieces which facilitate reducing the distortion of the applied magnetic field. However, such pole pieces are generally fabricated from expensive materials which may not be readily available.